Question: $\dfrac{9}{8} - \dfrac{2}{4} = {?}$
$ = {\dfrac{9 \times 1}{8 \times 1}} - {\dfrac{2 \times 2}{4 \times 2}} $ $ = {\dfrac{9}{8}} - {\dfrac{4}{8}} $ $ = \dfrac{{9} - {4}}{8} $ $ = \dfrac{5}{8}$